We show how to perform error correction of single qubit dephasing by encoding a single qubit into a minimum of three. This may be performed in a manner closely analogous to classical error correction schemes. Further, the resulting quantum error correction schemes are trivially generalized to the minimal encoding of arbitrarily many qubits so as to allow for multiqubit dephasing correction under the sole condition that the environment acts independently on each qubit.
@article{arxiv.quant-ph/9603024,
title = {Quantum error correction of dephasing in 3 qubits},
author = {Samuel L. Braunstein},
journal= {arXiv preprint arXiv:quant-ph/9603024},
year = {2007}
}